Power assist vehicle steering systems are well known in the art. One common type of power assist vehicle steering system utilizes a rack and pinion gear with an electric motor. Linear movement of the rack causes turning of steerable wheels of the vehicle. The electric motor may apply rotary force to a steering shaft, which is connected to the pinion gear, or the electric motor may apply linear force to the rack.
The electric motor is responsive to torque applied to the steering wheel. A torque sensor provides signals to a controller indicative of the amount of torque being applied. The controller controls the energization of the electric motor in response to the torque sensor signal to provide desired steering assist.